Is there a guide on the net to each type? Repair guides on line? Which types are easiest to convert to say an eyedropper or to accept some kind of converter?
These are the sites that I most frequently use for info/advice. This is no means a final, comprehensive list! I know others will chime in to help with more sites and advice! These should help get you started!
Regards,
Frank
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"When, in the course of writing events, it becomes self-evident that all pens are not created equal" (Federalist Frank)
We sell quality, known brands at reasonable prices!!
What do you consider "vintage," leaving aside it's actual meaning? The earliest fountain pens were pretty much all eyedroppers to begin with. Later, a variety of filling systems came and mostly went, including early attempts at metal or glass cartridges. Plastic cartridges came in much later, and mostly took off in the 1960s.
Most any pen with a solid non-metal barrel can be made into an eyedropper pen with a little silicone grease.